离子对反相高效液相色谱法测定阿仑膦酸钠的含量

以四丁基溴化铵为离子对试剂,采用离子对反相高校液相色谱法,配以示差折光检测器(RI)检测,建立了用于阿仑膦酸钠含量测定的分析方法.以Agilent CLC-ODS C18柱为固定相,流动相为V(甲醇):V(水)=10:90,含5mmol/LNH4H2PO4,2mmol/L四丁基溴化铵,1.5 mmol/L乙二胺四乙酸二钠,用NaoH调节pH至7.2),流速为1.0 mL/min,柱温为室温.方法的线性范围为80～720mg/L;回归方程为A=0.3971ρ-10.624,r=0.9993;方法的平均回收率为100.0%;RSD为0.76%.在该色谱条件下,得到阿仑膦酸钠主峰.     

Determination of aromatic sulfonates in coastal water by on-line Ion-pair solid-phase extraction/ion-pair liquid chromatography with UV detection

Summary A method for determining aromatic sulfonates in sea water is presented. Ion-pair solid phase extraction is coupled on-line to ion-pair liquid chromatography with UV detection. In the enrichment step, the recoveries from 100 mL of sea water were higher than 65% for most analytes. Linearity was good and detection limits were between 0.02 and 1 μgL⁻¹. The repeatability of the method, expressed as % of relative standard deviation (n=3) was between 1 and 15%. The method was checked in coastal water near the commercial port of Tarragona, where effluents from the petrochemical industry are discharged. All the samples taken were found to contain 2-naphthalenesulfonate.     

Determination of selenoamino acids using two-dimensional ion-pair reversed phase chromatography with on-line detection by inductively coupled plasma mass spectrometry

Analytical methods for the speciation of nine selenium species (selenite, selenate, selenourea, trimethylselenonium ion, selenocystamine, selenocystine, selenocysteine, selenomethionine and selenoethionine) that are commonly encountered in biological and environmental samples were developed. Good separation was achieved by either a mixed ion-pair reversed phase chromatography (LiChrosorb RP 18, 2.5 mM 1-butanesulfonate-8 mM tetramethylammonium hydroxide-4 mM malonic acid-0.05% methanol, pH 4.5) or a conventional ion-pair reversed phase chromatography (Inertsil ODS, 10 mM tetraethylammonium hydroxide-4.5 mM malonic acid, pH 6.8) with on-line ICP-MS detection. Using a 20-μl sample loop, low detection limits around 1 ng ml⁻¹ expressed as Se were achieved for the examined selenium species. The methods were used for the determination of selenoamino acids in a selenium nutritional supplement. The developed methods were found to be rather robust. No alteration of the separation was observed when the protease enzymatic extracts were analyzed without dilution. Both water extracts and enzymatic extracts were chromatographed first with the mixed ion-pair reversed phase chromatographic system, then the major chromatographic peaks were collected and analyzed by the second ion-pair reversed phase chromatographic system for a further verification of their identity. Selenomethionine was found to be the major selenium species in the supplement. A major unknown species, probably Se-adenosylhomocysteine, could be determined in the extracts. A biological reference material, Dolt-2, was also examined for the selenoamino acids. Selenocystine and selenomethionine could be detected in its enzymatic extract, suggesting that Dolt-2 may be used as a reference material for the identification of selenoamino acids in biological and environmental samples. As selenoethionine does not occur naturally in the investigated samples, it is added as an internal standard in this study.     

Rapid analysis of opium alkaloids by ion-pair high performance liquid chromatography

A new procedure for the rapid analysis of four major opium alkaloids is described using ion-pair, reversedphase high performance liquid chromatography and recently developed radial compression column technology. The solvents were aqueous 10mM potassium perchlorate with 5.0mM n-butylamine (pH 3.0) and pure acetonitrile. A gradient was run for five minutes from 10% to 70% acetonitrile and held at that level for two minutes. Flow rates were 3 ml/min. Two column packing materials were compared with this solvent system: standard C-18 packing and a fully-end-capped C-18 material. Results obtained with the fully-end-capped C-18 packing and the two solvent ion-pair gradient showed elution times under six minutes, with greater sensitivity (<50 nanograms) than previous systems.     

Determination of iodine anion in dried kelp and iodized throat tablets by reversed-phase ion-pair liquid chromatography with direct UV detection

Summary In this paper, the amount of iodine anion in dried kelp and iodized throat tablets was determined by reversed-phase ion-pair chromatography. A 300×4 mm I.D. columns packed with -Bondapak-C18 (5 m) was used and distilled water containing 10 mmol/l trimethylphenyl ammonium bromide was used as the eluent. UV detection at 231 nm was selected to monitor the iodine anion.     

Determination of furosine in milk samples by ion-pair reversed phase liquid chromatography

Summary An ion-pair, reversed-phase, liquid chromatographic procedure using UV detection for quantitation of furosine is described. The standard plot was linear (r>0.999) over a 5 ng range. An authentic synthesised sample of furosine was used for calibration. Commerical milk samples were analyzed by the described procedure.     

离子对反相高效液相色谱-蒸发光散射检测法测定三乙膦酸铝的含量

建立了以正丁胺为离子对试剂的反相高效液相色谱分析三乙膦酸铝含量的方法。采用Symmetry Shield RP18色谱柱分离,以甲醇-0.5%正丁胺水溶液(冰乙酸调节pH 5.0)(体积比为8:92)为流动相,流速为0.8 mL/min,蒸发光散射检测器(ELSD)检测。在上述条件下,三乙膦酸铝与其主要杂质亚磷酸盐、硫酸盐可以获得分离。在100～1200 mg/L范围内,进样质量与峰面积的双对数值呈良好的线性关系。100 mg/L和1000 mg/L两种质量浓度添加水平的回收率分别为100.58%和99.53%,其相对标准偏差(RSD)分别为0.62%和0.49%。该方法简便快捷,为三乙膦酸铝的定量分析提供了更加有效可靠的方法。     

Determination of lipoperoxide in animal tissue by ion-pair reversed phase high performance liquid chromatography

An ion-pair reversed phase high performance liquid chromatographic method was developed for the quantitative determination of lipoperoxide (as malondialdehyde, MDA) in animal tissue using a ODS column and a mobile phase of methanol + phosphate buffer (53:47 v/v, pH 6.5). Tetrabutylammonium bromide was used as an ion-pair reagent and the detection wavelength was set at 532 nm. The method was sensitive, accurate and simple. A linear relationship was obtained between the peak height and the amount of MDA from 50 nmol/L to 1200 nmol/L and the lower limit of detection of MDA was 15 nmol/L (signal-to-noise ratio greater than 2), and the coefficient of variation at the 200 nmol/L level was 3.7% (n = 7). The results correlated well with those from the 2-thiobarbituric acid colorimetric method. The method has been used in the pathogenic studies of cerebral ischemia and acute renal failure for the determination of trace lipoperoxide.     

Determination of the cephalosporin Ro 13-99041 in plasma,urine, and bile by means of ion-pair reversed phase chromatography

An HPLC method has been developed for the determination of the cephalosporin antibiotic Ro 13-9904 in plasma, urine, and bile of dogs and of human volunteers using the technique of ion-pair chromatography with a LiChrosorb RP-18 column. The three mobile phases employed contained tetrapentyl-, tetraoctyl- and hexadecyltrimethyl-ammonium bromide, respectively, as lipophilic counterions. The chromatographic conditions chosen allowed simple and rapid sample preparation. Plasma was deproteinized with ethanol and the supernatant was directly injected onto the column; urine and bile were diluted with mobile phase and injected without any purification. The detection limit for the cephalosporin was about 0.5 μg/ml for plasma samples and approximately 5 μg/ml for bile and urine.     

高效液相色谱化学发光法测定血清中左羟丙哌嗪

在H2SO4介质中, KMnO4氧化左羟丙哌嗪产生化学发光, 甲醛可增敏上述化学发光, 在此基础上建立了反相高效液相色谱(RP-HPLC)分离, 柱后化学发光检测左羟丙哌嗪的新方法, 并成功应用于血清中左羟丙哌嗪的测定. 在优化的实验条件下, 该法测定左羟丙哌嗪的线性范围为1.0×10-7～1.0×10-5 g/mL, 检出限(3σ)为3×10-8 g/mL. 对2.0×10-6 g/mL的左羟丙哌嗪进行11次平行测定, 其相对标准偏差为2.3%.     

Determination of tylosin and related macrolides in fermentation broth by gradient elution ion-pair liquid chromatography

Summary A gradient elution ion-pair HPLC assay was developed for the analysis of tylosin and related macrolides in fermentation broth. The effect of the ion-pair agent concentration and identity was studied to optimize the reproducibility of the separation. The assay compares favorably with the biological assay and is sufficiently durable for the analysis of many samples per column.     

Determination of acrylamide and methacrylamide by normal phase high performance liquid chromatography and UV detection

A method using normal phase high performance liquid chromatography (NP-HPLC) with UV detection was developed for the analysis of acrylamide and methacrylamide. The method relies on the chromatographic separation of these analytes on a polar HPLC column designed for the separation of organic acids. Identification of acrylamide and methacrylamide is approached dually, that is directly in their protonated forms and as their hydrolysis products acrylic and methacrylic acid respectively, for confirmation. Detection and quantification is performed at 200 nm. The method is simple allowing for clear resolution of the target peaks from any interfering substances. Detection limits of 10 microg L(-1) were obtained for both analytes with the inter- and intra-day RSD for standard analysis lying below 1.0%. Use of acetonitrile in the elution solvent lowers detection limits and retention times, without impairing resolution of peaks. The method was applied for the determination of acrylamide and methacrylamide in spiked food samples without native acrylamide yielding recoveries between 95 and 103%. Finally, commercial samples of french and roasted fries, cookies, cocoa and coffee were analyzed to assess applicability of the method towards acrylamide, giving results similar with those reported in the literature.     

Determination of linear alkylbenzene sulfonates by ion-pair solid-phase extraction and high-performance liquid chromatography

In this paper, the potential use of multiwalled carbon nanotubes (MWCNTs) as solid phase extraction (SPE) adsorbent was evaluated for preconcentration of linear alkylbenzene sulfonates (LAS) using ion-pair (IP)-SPE with tetrabutylammonium hydroxide (TBAH). The LAS homologues present in the aqueous sample were ion-paired with TBAH and the solution was passed through the MWCNT cartridges. The analytes retained in the cartridge were eluted with methanol and the concentrated methanol extract was analysed by HPLC-UV. In order to obtain the satisfactory recovery of LAS homologues, various parameters including the type and amount of the ion-pair reagents, the desorption and enrichment conditions such as the effect of eluent and its volume, pH, the flow rate, the ultrasonic time of sample, and the volume of sample solution were systematically optimized. Under the optimal conditions, LAS homologues could be easily extracted by the proposed SPE cartridge. The favorable limits of detection (LOD) for LAS homologues were in the range from 0.02 to 0.03 μg L⁻¹, and the relative standard deviations (RSDs) were 1.55-2.54% for 10 μg L⁻¹ LAS (n = 6). The proposed method has been successfully applied for the analysis of LAS homologues in aqueous environmental samples. A comparison study with ion-pair solid extraction on MWCNTs, C8 and C18 as adsorbents for LAS demonstrated that ion pair-based solid extraction on MWCNTs adsorbent was advantageous over C8 and C18, the widely used traditional adsorbents.     

Direct separation and detection of biogenic amines by ion-pair liquid chromatography with chemiluminescent nitrogen detector

Analysis of biogenic amines is critical to pharmaceutical and food industry due to their biological importance. For many years, the determination of biogenic amines has relied on high performance liquid chromatography (HPLC) coupling with pre-, on-, or post-column derivatization procedures to enable UV or fluorescent detections. In this study, 14 biogenic amines were separated on a Phenomenex Luna Phenyl-Hexyl column by an ion-pair liquid chromatography method using perfluorocarboxylic acids as ion-pair reagents and detected by a chemiluminescent nitrogen detector (CLND). This direct separation and detection HPLC method eliminated the time consuming and cumbersome derivatization procedures. Compared with HPLC-UV (post-column derivatization with ninhydrin) and HPLC-charged aerosol detector (CAD) methods, this HPLC-CLND technique provided narrower peaks, better baselines, and improved separations and detections. Excellent linearity was acquired by CLND for each of the 14 biogenic amines ranging from less than 1 ng to about 1000 ng (on-column weights). The relative response factors determined by this LC-CLND method were proportional to the numbers of nitrogen atoms in each compound, which has been the characteristic of the equimolar determinations by CLND. In addition, a number of samples including beer, dairy beverage, herb tea, and vinegar were analyzed by the LC-CLND method with satisfactory precision and accuracy.     

Determination of L-carnitine in food supplement formulations using ion-pair chromatography with indirect conductimetric detection

A novel method for the determination of L-carnitine in food supplement formulations was developed and validated, using ion-pair chromatography with indirect conductimetric detection. The chromatographic method was based on a non-polar (C18) column and an aqueous octanesulfonate (0.64 mM) eluent, acidified with trifluoroacetic acid (5.2 mM). The retention time was 5.4 min and the asymmetry factor 0.65. A linear calibration curve from 10 to 1000 microg/ml (r= 0.99998), with a detection limit of 2.7 microg/ml (25 microl injection volume), a repeatability %RSD of 0.8 (40 microg/ml, n = 5) and reproducibility %RSD of 2.6 were achieved. The proposed method was applied for the determination of carnitine in oral solutions and capsules. No interference from excipients was found and the only pretreatment step required was the appropriate dilution with the mobile phase. Recovery from spiked samples was ranged from 97.7 to 99.7% with a precision (%RSD, n = 3) of 0.01-2.1%.     

Determination of amphetamine and methamphetamine in urine by solid phase extraction and ion-pair liquid chromatography-electrospray-tandem mass spectrometry

A method using a solid phase extraction (SPE) and ion-pair liquid chromatography-electrospray-tandem mass spectrometry (LC-ES-MS/MS) was developed for determination of amphetamine (Amp) and methamphetamine (mAmp) in urine samples. A reversed phase C₁₈ column was utilized for LC separation and MS/MS was used for detection. Trifluoroacetic acid was added to the mobile phase as an ion-pairing reagent. MS² was employed for quantitative determination. In addition, d₈-amphetamine and d₈-methamphetamine were used as internal standards. An Oasis HLB SPE cartridge, which has hydrophilic and lipophilic functions, was utilized for sample pre-treatment. Recoveries ranging from 97.3 to 102.1% were measured. Good linear ranges, 5-500 ng/ml, for Amp and mAmp were determined. The detection limit of each analytical compound, based on a signal-to-noise ratio of 3, was approximately 1 ng/ml. The applicability of this newly developed method was examined by analyzing several urine samples from drug users.     

Fast analysis of thiocyanate by ion-pair chromatography with direct conductivity detection on a monolithic column

Fast analysis of thiocyanate by ion-pair chromatography using a silica-based monolithic column and direct conductivity detection was carried out. Chromatographic separation was performed on a Chromolith Speed ROD RP-18e using tetrabutylammonium hydroxide （TBA）-phthalic acid-acetonitrile as eluent. The effects of eluent concentration, eluent pH value, column temperature and flow rate on retention time of thiocyanate were investigated. The optimized chromatographic conditions for the determination of thiocyanate were as follows： 0.25 mmol/L TBA-0.18 mmol/L phthalate-7% acetonitrile （pH 5.5） as eluent, column temperature of 30 ℃, and flow rate of 6.0 mL/min. Retention time of thiocyanate was less than 1 min under the conditions. Common anions （Cl^-, NO3 , SO42 and I^- ） did not interfere with the determination of thiocyanate. Detection limit （S/N = 3） of thiocyanate was 0.96 mg/L. Calibration graph between peak area and the concentration of thiocyanate was linear in the range of 2.0- 100.0 mg/L. Relative standard deviation （RSD） of chromatographic peak area was 1.4% （n = 5）. This method has been applied to the determination of thiocyanate in ionic liquids. Recoveries of thiocyanate after spiking were 100.5%.     

Determination of risedronate in rat plasma samples by ion-pair high-performance liquid chromatography with UV detector

In the present work, an analytical method for determination of risedronate, a member of bisphosphonates, is described for the routine analysis in rat plasma. Sample pre-treatment involves protein precipitation, co-precipitation with calcium at alkaline pH, hydrolysis of possible derivatives of pyrophosphate and reprecipitation. A good separation was obtained by using a reversed-phase column (Hypersil ODS-2 C₁₈, 4.6 mm × 250 mm, 5 μm). The mobile phase was an aqueous solution of buffer (contained 1.5 mM EDTA-2Na, 1 mM sodium etidronate, 11 mM sodium phosphate and 5 mM tetrabutylammonium bromide as ion-pair reagent) - methanol (88:12, v/v) adjusted to pH 6.75 using 1 M NaOH. The flow rate was 1 ml min⁻¹. UV detection (λ = 262 nm) was used to quantitate risedronate in the concentration range of 10-500 ng ml⁻¹. The limit of detection and quantitation for risedronate were 7 and 10 ng ml⁻¹, respectively. The method was applied successfully to plasma samples from Wistar rats undergoing oral administration of risedronate mini-pills. Precision, extraction recoveries, as well as accuracy results, were satisfactory and no interference was found at the retention time of risedronate. Hence, the method is suitable for monitoring risedronate in rat plasma.     

Determination of tetraethyl ammonium by ion-pair chromatography with indirect ultraviolet detection using 4-aminophenol hydrochloride as background ultraviolet absorbing reagent

A method was developed for the determination of tetraethyl ammonium (TEA) by reversed-phase ionpair chromatography with indirect ultraviolet detection. Chromatographic separation was achieved on a reversed-phase C18 column using background ultraviolet absorbing reagent - ion-pair reagent - organic solvent as mobile phase. The effects of the background ultraviolet absorbing reagents, detection wavelength, ion-pair reagents, organic solvents and column temperature on the determination method were investigated and the retention rules discussed. Results found that TEA could be successfully analyzed by using 0.7 μmol/L 4-aminophenol hydrochloride and 0.15 μmol/L 1-heptanesulfonic acid sodium mixed with 20% (v/v) methanol asmobile phase at a UV detection wavelength of 230 nm. Under these conditions, the retention time of tetraethyl ammonium was 2.85 min. The detection limit (S/N = 3) for TEA was 0.06 mg/L. The relative standard deviations (n = 5) for peak area and retention time were 0.35% and 0.02%, respectively. The method has been successfully applied to the determination of synthesized tetraethyl ammonium bromide. Recovery of tetraethyl ammonium after spiking was 99.1%.